In general, this proposal is designed to study the basic mechanisms involved in the expression of cellular immunity in man. With the information that is gathered, we plan to apply these findings to patients who have diseases associated with depressed cell-mediated immunity. It also follows that further insight into the mechanisms of cellular immunity may lead to manipulation of the immune response in such patients. Results obtained from these studies may be applied to other areas such as transplantation and tumor immunity. The specific goals are: 1) an investigation of the lymphocyte mediator, leukocyte inhibitory factor of LIF, with regard to its characterization as an enzyme and the possibility of developing a biochemical assay for its detection as well as an examination of its effect on polymorphonuclear leukocyte function. 2) to investigate the role of histamine receptor bearing lymphocytes in the modulation of immune responses. We will focus on the role of these cells in MIF production and proliferation. We will also investigate a product of these suppressor cells, a histamine induced suppressor factor with regard to its physico-chemical characterization and its mechanism of action. 3) studies into the maternal - fetal relationship. We are evaluating the biologic significance of an IgG antibody in the serum of normal multiparous women. We are trying to determine the specificity of this antibody as well as its role in the maintenance of a normal term pregnancy.